Two men, tired from work, visit the town of Chichibu to enjoy their favorite hobby - exploring caves. But little do they know, the town has been secretly protected by the descendants of the righteous Shinobi ninja since the Sengoku period. The two unlucky friends accidentally break a spell that awakens two colossal beasts, Jaron and Goura. The area’s rival clans manipulate them into a fierce battle, bringing chaos to the area. But a righteous female ninja steps up, wanting to stop the destruction and restore the seal. Can she defeat the evil ninjas that stand in her way before Chichibu is completely destroyed by two kaiju?

Set in World War II, the film depicts the story of the real-life Japanese battleship, the Yamato, which is confronted in the Pacific Ocean by giant monsters, including the most fearsome of them all, Reigo.